Heat exchanger with integral features

ABSTRACT

A counterflow heat exchanger configured to exchange thermal energy between a first fluid flow at a first pressure and a second fluid flow at a second pressure less than the first pressure includes a first fluid inlet, a first fluid outlet fluidly coupled to the first fluid inlet via a core section, a second fluid inlet, and a second fluid outlet fluidly coupled to the second fluid inlet via the core section. A heating arrangement is configured to heat the second fluid inlet to prevent ice ingestion via the second fluid inlet.

BACKGROUND

Exemplary embodiments pertain to the art of heat exchangers.

Heat exchangers are utilized in various applications to exchange thermalenergy from a first fluid stream to a second fluid stream. For example,in an aircraft environmental control system (ECS), a heat exchanger isutilized to exchange thermal energy between a relatively low pressure,low temperature RAM airflow and a relatively high pressure, hightemperature bleed air flow from a gas turbine engine compressor. Suchthermal energy exchange cools the bleed air flow upstream of an aircycle machine of the ECS.

Further, in an ECS heat exchangers are utilized as condensers whererelatively high temperature, humid air is cooled by a cold airstream.One such condenser is a “sub-freezing” condenser, which utilizes an iceand/or snow-laden cold airstream to cool a hot airflow and condensewater therefrom. The ice and snow pose significant risks for heatexchanger operation, as it may clog heat exchanger passages, increasingpressure losses and diminishing heat exchanger and ECS efficiency andperformance.

BRIEF DESCRIPTION

In one embodiment, a counterflow heat exchanger configured to exchangethermal energy between a first fluid flow at a first pressure and asecond fluid flow at a second pressure less than the first pressureincludes a first fluid inlet, a first fluid outlet fluidly coupled tothe first fluid inlet via a core section, a second fluid inlet, and asecond fluid outlet fluidly coupled to the second fluid inlet via thecore section. A heating arrangement is configured to heat the secondfluid inlet to prevent ice ingestion via the second fluid inlet.

Additionally or alternatively, in this or other embodiments the heatingarrangement includes one or more bypass passages extending from thefirst fluid inlet toward the second fluid inlet, bypassing the coresection, the one or more bypass passages configured to direct a bypassportion of the first fluid flow past the second fluid inlet.

Additionally or alternatively, in this or other embodiments the bypassportion conductively heats the second fluid inlet as the bypass portionpasses the second fluid inlet.

Additionally or alternatively, in this or other embodiments the one ormore bypass passages extend to a first outlet header disposed downstreamof the core section, the first outlet header fluidly connected to thefirst fluid outlet.

Additionally or alternatively, in this or other embodiments the flow ofthe bypass portion is configured to be modulated based on conditions atthe second fluid inlet.

Additionally or alternatively, in this or other embodiments the coresection includes a plurality of first fluid passages configured toconvey the first fluid flow from the first fluid inlet toward the firstfluid outlet, and a plurality of second fluid passages configured toconvey the second fluid flow from the second fluid inlet toward thesecond fluid outlet such that the first fluid flow exchanges thermalenergy with the second fluid flow at the core section. Each first fluidpassage of the plurality of first fluid passages has a circularcross-section.

Additionally or alternatively, in this or other embodiments theplurality of first fluid passages are connected to the plurality ofsecond fluid passages via one or more web portions.

Additionally or alternatively, in this or other embodiments the one ormore web portions define at least a portion of the passage wall of theplurality of first fluid passages.

Additionally or alternatively, in this or other embodiments a first flowdirection of the first fluid flow through the first fluid inlet isnonparallel to the first flow direction of the first fluid flow throughthe plurality of first fluid passages.

Additionally or alternatively, in this or other embodiments a secondflow direction of the second fluid flow through the second fluid inletis nonparallel to the second flow direction of the second fluid flowthrough the plurality of second fluid passages.

Additionally or alternatively, in this or other embodiments a first flowdirection of the first fluid flow through the plurality of first fluidpassages is opposite a second flow direction of the second fluid flowthrough the plurality of second fluid passages.

Additionally or alternatively, in this or other embodiments the heatexchanger is formed from a polymeric material.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 is a perspective view of an embodiment of a heat exchanger;

FIG. 2A is a plan view of a first flow path of an embodiment of a heatexchanger;

FIG. 2B is a plan view of a second flow path of an embodiment of a heatexchanger;

FIG. 3 is a partial cross-sectional view of an embodiment of a coresection of a heat exchanger;

FIG. 4 is a plan view of an inlet heating arrangement of a heatexchanger;

FIG. 5 is a cross-sectional view of an inlet heating arrangement of aheat exchanger;

FIG. 6 is a cross-sectional view of a fluid passage drain arrangement ofa heat exchanger;

FIG. 7 is another cross-sectional view of a fluid passage drainarrangement of a heat exchanger;

FIG. 8 is an end view of a fluid passage drain arrangement of a heatexchanger; and

FIG. 9 is another view of a fluid passage drain arrangement of a heatexchanger.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosedapparatus and method are presented herein by way of exemplification andnot limitation with reference to the Figures.

Referring now to FIG. 1, illustrated is a schematic view of anembodiment of a heat exchanger 10. The heat exchanger 10 facilitates anexchange of thermal energy between a first fluid flow 12 and a secondfluid flow 14 directed through the heat exchanger 10. In someembodiments, the first fluid flow 12 is a relatively high temperature,high pressure fluid flow such as a bleed airflow from a compressor of agas turbine engine. Further, in some embodiments the second fluid flow14 is a relatively low temperature, low pressure fluid flow such as RAMairflow for use by an aircraft environmental control system (not shown).

As shown in FIG. 1 and in FIG. 2A, the heat exchanger 10 includes afirst fluid flow path 16 along which the first fluid flow 12 is directedthrough the heat exchanger 10 from a first inlet 18 to a first outlet20. Similarly, as shown in FIGS. 1 and 2B, the heat exchanger 10includes a second fluid flow path 22 along which the second fluid flow14 is directed from a second inlet 24 to a second outlet 26. The heatexchanger 10 is a counter-flow heat exchanger 10 such that at a coresection 28 of the heat exchanger 10, the first fluid flow 12 and thesecond fluid flow 14 are flowing in substantially opposite directions.

A cross-sectional view of a portion of the core section 28 of the heatexchanger 10 is illustrated in FIG. 3. The core section 28 includes aplurality of first passages 30 to convey the first fluid flow 12therethrough, and a plurality of second passages 32 to convey the secondfluid flow 14 therethrough. The first fluid passages 30 are circular incross-section. This allows the first fluid passages 30 to convey thehigh pressure first fluid flow 12, and to allow for the use of lowerstrength polymeric materials in place of the traditional metal materialsin forming the first fluid passages 30, the second fluid passages 32 andthe core section 28. For some materials the first fluid passages may beany polygonal shape that maximizes primary heat transfer area betweenthe first and the second fluid. The second fluid passages 32 are locatedbetween adjacent first fluid passages 30 and are separated from thefirst fluid passages 30 by web sections 34, which at least partiallyform walls of the first fluid passages 30. While in some embodiments,the second fluid passages 32 may have a circular cross sections, thesecond fluid passages 32 may have other cross-sectional shapes due tothe lower pressure of the second fluid flow 14.

Referring again to FIG. 2A, a first inlet manifold 36 is located betweenthe first inlet 18 and the core section 28, and a first outlet manifold38 is located between the core section 28 and the first outlet 20. Thefirst inlet manifold 36 is configured to minimize contraction losses attransition area between the first inlet manifold 36 and the first fluidpassages 30 of the core section 28. This includes aerodynamic design ofthe leading edges in the header section, optimized header hydraulicdiameter to balance pressure loss and the core, etc. The first inletmanifold 36 includes one or more first inlet vanes 40 located betweenthe first inlet 18 and the core section 28 to distribute the first fluidflow 12 to the plurality of first fluid passages 30. While theembodiment of FIG. 2A shows one first inlet vane 40, it is to beappreciated that that other quantities of first inlet vanes 40, such as2, or 3 or more first inlet vanes 40, may be utilized to distribute thefirst fluid flow 12 in a selected way. The quantity and arrangement offirst inlet vanes 40 may depend on, for example, a first inlet angle 42between the first inlet 18 and the core section 28. These vanes are alsodesigned to provide structural strength in the header/manifold sectionof the heat exchangers. Additionally good flow distribution with minimalflow pressure loss can also be attained by optimizing the outer moldline shapes of the inlet and outlet manifolds. Inlet and outletmanifolds could have different designs of the internal vanes and theirouter mold line shapes for enhancing flow distribution and reducingpressure loss.

Similarly, the first outlet manifold 38 includes one or more firstoutlet vanes 44 located between the core section 28 and the first outlet20 to smoothly direct the first fluid flow 12 from the core section 28to the first outlet 20, minimizing losses. While the embodiment of FIG.2A shows one first outlet vane 44, it is to be appreciated that thatother quantities of first outlet vanes 44 such as 2, or 3 or more firstoutlet vanes 44, may be utilized to direct the first fluid flow 12 in aselected way. The quantity and arrangement of first outlet vanes 44 maydepend on, for example, a first outlet angle 46 between the first outlet20 and the core section 28.

Referring again to FIG. 2B, a second inlet manifold 46 is locatedbetween the second inlet 24 and the core section 28, and a second outletmanifold 48 is located between the core section 28 and the second outlet26. The second inlet manifold 46 is configured to minimize contractionlosses at transition area between the second inlet manifold 46 and thesecond fluid passages 32 of the core section 28. This is achieved bysmoothly lofting the flow cross-section from the core channels, e.g.,circular tubes, to a rectangular slot in the headers. This transitionregion is designed such that flow separation and blockage is minimizedin the transition region. One way to achieve that is maintainingconstant flow cross sectional areas for both flow streams in thetransition region. The second inlet manifold 46 includes one or moresecond inlet vanes 50 located between the second inlet 24 and the coresection 28 to distribute the second fluid flow 14 to the plurality ofsecond fluid passages 32. While the embodiment of FIG. 2B shows onesecond inlet vane 50, it is to be appreciated that that other quantitiesof second inlet vanes 50, such as 2, or 3 or more second inlet vanes 50,may be utilized to distribute the second fluid flow 14 in a selectedway. The quantity and arrangement of second inlet vanes 50 may dependon, for example, a second inlet angle 52 between the second inlet 24 andthe core section 28.

Similarly, the second outlet manifold 48 includes one or more secondoutlet vanes 54 located between the core section 28 and the secondoutlet 26 to smoothly direct the second fluid flow 14 from the coresection 28 to the second outlet 26, minimizing losses. While theembodiment of FIG. 2B shows one second outlet vane 54, it is to beappreciated that that other quantities of second outlet vanes 54 such as2, or 3 or more second outlet vanes 54, may be utilized to direct thesecond fluid flow 14 in a selected way. The quantity and arrangement ofsecond outlet vanes 54 may depend on, for example, a second outlet angle56 between the second outlet 26 and the core section 28.

While the vanes 40, 44, 50 and 54 are included to direct the fluid flows12, 14 through the heat exchanger 10 smoothly and efficiently, the vanes40, 44, 50 and 54 also provide structural rigidity to the heat exchanger10. This further enables the use of polymeric materials such as epoxyresins, polyurethane materials, or the like in formation of the heatexchanger 10.

Referring now to FIGS. 4 and 5, as stated above, the ingestion of iceand/or snow through the second inlet 24 reduces performance of the heatexchanger 10 by, for example, clogging the second inlet 24 and/or thesecond fluid passages 32. To enable ice-free operation of the heatexchanger 10, the heat exchanger 10 includes a heating apparatus locatedat the second inlet 24. More particularly, the heat exchanger 10includes one or more bypass passages 58 extending from the first inlet18 toward the second inlet 24. The bypass passages 58 direct a bypassportion 60 of the first fluid flow 12 toward the second inlet 24,bypassing the core section 28. As the bypass portion 60 passes thesecond inlet 24, the second inlet 24 is heated via conduction. Theheated second inlet 24 reduces ice and/or snow ingestion at the secondinlet 24, thus improving performance of the heat exchanger 10. Afterpassing the second inlet 24, the bypass portion 60 is directed throughthe first outlet 20 via the first outlet manifold 38. While in theembodiment illustrated, the flow of the bypass portion 60 is constant,in other embodiments the flow of the bypass portion 60 may be modulatedvia, for example, one or more valves (not shown) operable to open orclose directing flow through the bypass passages 58 when, for example,the second fluid flow 14 is at a sub-freezing temperature.

Referring now to FIGS. 6-8, during operating of the heat exchanger 10condensation may form on an interior on each of the first fluid passages30, due to the high relative humidity of the first fluid flow 12. It isdesired to remove the condensation from the heat exchanger 10 such thatthe condensation does not proceed through the first outlet 20. As shownin FIG. 6, the first fluid passages 30 are provided with scupper drains62 into which the condensation is urged by flow of the first fluid flow12 through the first fluid passages 30. In some embodiments, the scupperdrains 62 comprise openings or notches in the first fluid passages 30.

As shown in FIG. 7, the scupper drains 62 of the first fluid passages 30of each passage layer 64 of the core section 28 are connected by a layerdrain 66. The layer drain 66 collects the condensation from the scupperdrains 62 of the passage layer 64 and directs the condensation to alayer end 68. As shown in FIG. 8, a core drain 70 is located at thelayer end 68, to collect the condensation from the layer drains 66 anddrain the condensation downwardly along an outer surface 72 out the heatexchanger 10. The core drain 70 may be, for example a tubular elementextending along the outer surface 72, or alternatively may be a notch orthe like in the outer surface 72 of the heat exchanger 10. The coredrain 70 includes a drain outlet 74 through which the condensation exitsthe heat exchanger 10.

It is expected that the condensate flowing through the scupper drains 62will entrain some air flow from the bulk flow. Hence, a water removaland air re-entrainment apparatus is utilized. Once the condensatemixture comes out of the HX core through the core drains 70, it enters awater removal chamber 76, shown in FIG. 9. The water removal chamber 76includes multi-passage tortuous flow channels 78 which slow down theair-water mixture such that water/condensate flows down due to gravityinto a water reservoir. This reservoir is ultimately connected to thedrain outlet 74 from which the condensate can freely flow out and may beutilized in other parts of the ECS 10. The remaining air is re-entrainedback into the HX main flow path through re-entrainment holes 80 that arelocated in the HX outlet manifold. Some local features near there-entrainment holes 80 can be added to decrease the local flow staticpressure such that the overflow air can be effectively re-entrained intothe main flow stream. These features reduce the air leakage associatedwith water separation during ECS 10 operation.

With this drainage arrangement, a separate water removal systemdownstream of the heat exchanger 10 is not necessary, which is asignificant savings in component cost and volume. Further, the heatexchanger 10 features disclosed herein may be integrally formed withpolymeric materials via molding or additive manufacturing methods.Further, the use of polymeric materials has additional benefits inreduced weight, improved corrosion resistance, low surface energy toassist in ice removal, and reduction in raw material costs, as comparedto heat exchangers formed with a traditional metal construction.

The term “about” is intended to include the degree of error associatedwith measurement of the particular quantity based upon the equipmentavailable at the time of filing the application.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,element components, and/or groups thereof.

While the present disclosure has been described with reference to anexemplary embodiment or embodiments, it will be understood by thoseskilled in the art that various changes may be made and equivalents maybe substituted for elements thereof without departing from the scope ofthe present disclosure. In addition, many modifications may be made toadapt a particular situation or material to the teachings of the presentdisclosure without departing from the essential scope thereof.Therefore, it is intended that the present disclosure not be limited tothe particular embodiment disclosed as the best mode contemplated forcarrying out this present disclosure, but that the present disclosurewill include all embodiments falling within the scope of the claims.

What is claimed is:
 1. A counterflow heat exchanger configured toexchange thermal energy between a first fluid flow at a first pressureand a second fluid flow at a second pressure less than the firstpressure, comprising: a first fluid inlet; a first fluid outlet fluidlycoupled to the first fluid inlet via a core section; a second fluidinlet; a second fluid outlet fluidly coupled to the second fluid inletvia the core section; and a heating arrangement configured to heat thesecond fluid inlet to prevent ice ingestion via the second fluid inlet;wherein the heating arrangement comprises one or more bypass passagesextending from the first fluid inlet toward the second fluid inlet,bypassing the core section, the one or more bypass passages configuredto direct a bypass portion of the first fluid flow from the first fluidinlet past the second fluid inlet, the one or more bypass passagesextending across the second fluid inlet, the second fluid inlet and theone or more bypass passages spaced apart from the core section by asecond fluid inlet manifold fluidly connecting the second fluid inlet tothe core section; and wherein the bypass portion of the first fluid flowis modulated based on conditions at the second fluid inlet via one ormore valves; and wherein a first flow direction of the first fluid flowinto the first fluid inlet is nonparallel to a second flow direction ofthe second fluid flow into the second fluid inlet.
 2. The counterflowheat exchanger of claim 1, wherein the bypass portion conductively heatsthe second fluid inlet as the bypass portion passes the second fluidinlet.
 3. The counterflow heat exchanger of claim 1, wherein the one ormore bypass passages extend to a first outlet header disposed downstreamof the core section, the first outlet header fluidly connected to thefirst fluid outlet.
 4. The counterflow heat exchanger of claim 1,wherein the core section comprises: a plurality of first fluid passagesconfigured to convey the first fluid flow from the first fluid inlettoward the first fluid outlet; and a plurality of second fluid passagesconfigured to convey the second fluid flow from the second fluid inlettoward the second fluid outlet such that the first fluid flow exchangesthermal energy with the second fluid flow at the core section; whereineach first fluid passage of the plurality of first fluid passages has acircular cross-section.
 5. The counterflow heat exchanger of claim 4,wherein the plurality of first fluid passages are separated from theplurality of second fluid passages via one or more web portions.
 6. Thecounterflow heat exchanger of claim 5, wherein the one or more webportions define at least a portion of the passage wall of the pluralityof first fluid passages.
 7. The counterflow heat exchanger of claim 4,wherein the first flow direction of the first fluid flow through thefirst fluid inlet is nonparallel to the first flow direction of thefirst fluid flow through the plurality of first fluid passages.
 8. Thecounterflow heat exchanger of claim 4, wherein the second flow directionof the second fluid flow through the second fluid inlet is nonparallelto the second flow direction of the second fluid flow through theplurality of second fluid passages.
 9. The counterflow heat exchanger ofclaim 4, wherein the first flow direction of the first fluid flowthrough the plurality of first fluid passages is opposite the secondflow direction of the second fluid flow through the plurality of secondfluid passages.
 10. The counterflow heat exchanger of claim 1, whereinthe heat exchanger is formed from a polymeric material.